1.0 Field of the Invention
The present invention relates to a field of military activities involving the determination and coordination of target locations and, more particularly, to a system particularly suited to determine the location of the muzzle from which an explosive projectile has been launched. Specifically, the present invention comprises an array of elevated or airborne sensors wherein all sensors are on a direct unencumbered path to a target of interest not burdened with the detection of reflected sound signals so that the target of interest may be accurately located.
2.0 Description of the Prior Art
Numerous techniques exist for detecting hostile weapon firing using aircraft, unmanned remotely piloted vehicles, human intelligence, and various ground based sensing systems. A system that uses human intelligence in cooperation with a rifle-target locator receiving global positioning system (GPS) information is capable of precisely determining the location coordinates of the target. One such system being described in U.S. Pat. No. 4,949,089, is herein incorporated by reference.
A system which detects and determines the location of muzzle blast sound generated by gun fire is also known and one such system is described in U.S. Pat. No. 2,962,696 ('696), which is herein incorporated by reference. The '696 patent utilizes cosine law microphones that serve as a sound wave energy detector for locating the placement of the gun from which the blast emanates. The system of the '696 patent suffers accuracy degradations because it is a land-base system and is subjected to the detection of unreliable reflections or echoes from the initial source of the sound. It is desired that a system be provided for detecting the location of a gun blast without encountering gun blast multi-path reflection or echo signals.
With the exception of a low altitude pilot aircraft visually spotting the weapon of an enemy and taking immediate action to destroy the weapon, prior art detection systems suffer some accuracy degradation for directing fire control to insure a proper response to a distant or concealed weapon of an enemy. Apart from the risk of detection by aircraft surveillance, detection may generally be avoided when the enemy employs night-time cover, weather conditions, camouflage concealment or other techniques.
Many types of acoustic ranging systems have been employed but most of these consist of ground-based sensing arrays. The ground-based sensing arrays must for the most part be deployed in friendly territory, and, as mentioned with reference to the '696 patent, are limited by spurious multi-path reflection signals. It is desired that a hostile weapon locator system be provided that does not suffer from the accuracy degradations encountered by ground-based sensing arrays. It is further desired that a hostile locating weapon system be provided that is of a low cost and yet sufficiently accurate to permit effective automated retaliatory strikes.